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11/14/2019 – Ephemeris – Saturn is not only Lord of the Rings, but also King of the Moons

November 14, 2019 Comments off

Ephemeris for Thursday, November 14th. Today the Sun will be up for 9 hours and 37 minutes, setting at 5:15, and it will rise tomorrow at 7:39. The Moon, 2 days past full, will rise at 6:57 this evening.

This news item is a month old, but it’d kind of cool. Jupiter may be the king of the planets, but it is not the king of the Moons. In a recent announcement from the International Astronomical Union. Saturn has edged out Jupiter in the number of moons that orbit it. Twenty new moons or satellites have been recently been discovered around the ringed planet bringing its total number up to 82. Jupiter’s total number of moons stands at 79. The discovery of the 20 latest moons was done with the Subaru 8.2 meter telescope on Mauna Kea on the island of Hawai’i by a group headed by Scott Sheppard of the Carnegie Institution for Science. 17 of these new satellites orbit Saturn in similar orbits backward from most of the rest of the moons.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

A diagram of Saturn's entire moon system and ring system

Bottom panel: The outer irregular moons of Saturn, with a scale of 1 pixel = 40,000 km. Moon groups, as well as ungrouped moons, are individually listed. They are graphed by their inclination, as well as the closest/furthest points in their orbit from Saturn (perichron and apochron) Middle panel: The middle moons of Saturn, with a scale of 1 pixel = 4,000 km. Although Saturn’s middle moons can be resolved, the inner moons and its rings are still difficult to resolve
Top panel: The inner moons of Saturn, with a scale of 1 pixel = 400 km. On the left, the rings of Saturn are labeled, and on the right, the inner moons are labeled. Click on the image to enlarge. Credit: Exoplanetaryscience.

Check it out in Bad Astronomy:  https://www.syfy.com/syfywire/another-score-for-saturn-20-newly-discovered-moons-for-the-ringed-planet.  The satellite diagram it contains shows Saturn not to scale with the satellite orbits.  At that scale Saturn would be a small dot.  These satellites are far out, really!

For more on all of Saturn’s moons:  https://en.wikipedia.org/wiki/Moons_of_Saturn.

 

07/09/2019 – Ephemeris – Saturn is opposite the Sun in the sky today

July 9, 2019 Comments off

Ephemeris for Tuesday, July 9th. Today the Sun will be up for 15 hours and 23 minutes, setting at 9:29, and it will rise tomorrow at 6:07. The Moon, at first quarter today, will set at 1:58 tomorrow morning.

Today Saturn will pass in opposition from the Sun at 12:12 p.m. It’s a time when Saturn will rise as the Sun sets, being opposite the Sun in the sky, and a time near its closest to the Earth at 841 million miles (1.354 billion km). Saturn orbits the Sun at a distance of 10 times the Earth’s distance, so Saturn’s distance from the Earth varies from 9 times to 11 times the Earth’s distance from the Sun. So it doesn’t change much in size in telescopes. This is unlike Mars which has a greater range of distances from the Earth. In telescopes the rings are the first one sees, with the planet nestled in the center. In small telescopes, it is a tiny but magnificent sight. It’s largest moon Titan is visible nearby.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Apparent sizes of Saturn_2019-20

Here’s the extremes in the apparent size of Saturn from solar opposition to conjunction. Created using Cartes du Ciel.

10/02/2018 – Ephemeris – I will give a talk on Saturn at the Traverse Area District Library tomorrow night

October 2, 2018 Comments off

Ephemeris for Tuesday, October 2nd. The Sun will rise at 7:42. It’ll be up for 11 hours and 39 minutes, setting at 7:21. The Moon, at last quarter today, will rise at 12:55 tomorrow morning.

Tomorrow night October 3rd at 7 p.m. I’ll be giving a talk at the main branch of the Traverse Area District Library on Woodmere Avenue, about the amazing discoveries made about Saturn, its rings and moons by the Cassini spacecraft and its Titan lander Huygens, spanning 7 years to get there and 13 orbiting Saturn among its rings and moons. The spacecraft made a planned plunge into Saturn’s atmosphere a year ago. The illustrated talk is called Remembering Cassini. Besides the numerical data sent back were images, some of which were made into videos, such as the landing of the Huygens probe on Titan. After the talk, if it will be clear, Saturn will be visible in the telescopes of the Grand Traverse Astronomical Society, along with other wonders of the skies.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendu

Cassini and Huygens
Cassini and Huygens from Remembering Cassini

06/28/2018 – Ephemeris – Saturn at opposition, what it means

June 28, 2018 Comments off

Ephemeris for Thursday, June 28th. Today the Sun will be up for 15 hours and 32 minutes, setting at 9:32, and it will rise tomorrow at 6:00. The Moon, at full today, will rise at 9:54 this evening.

Just before midnight last night Saturn was in opposition to the Sun. We’re not talking about an argument here. To the astronomer opposition simply means that a planet, in this case Saturn, is 180 degrees from the Sun, or opposite the Sun in the sky. It is a time when the planet rises at sunset and sets at sunrise. It is also a time when the planet is around its closest to the Earth. It’s not a big deal for Saturn, which is almost 10 times farther from the Sun than we are. However it is a big deal for a nearby planet like Mars, which at the end of July will be closer to us than at any time since 2003, at 35.8 million miles. That’s a big deal since Mars is a small planet, a bit more than half the size of the Earth.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

The apparent sizes of Saturn and Mars

The apparent sizes of Saturn and Mars as seen from the Earth at opposition and solar conjunction. All at the same scale. Created using Cartes du Ciel (Sky Charts).

04/02/2018 -Ephemeris – Mars is appearing to pass Saturn in the morning

April 2, 2018 Comments off

Ephemeris for Monday, April 2nd. The Sun will rise at 7:21. It’ll be up for 12 hours and 49 minutes, setting at 8:11. The Moon, 2 days past full, will rise at 10:40 this evening.

At 3:02 this afternoon the planet Mars will pass the planet Saturn. The event is called a conjunction, which simply means they are on nearly the same line of sight from the Earth, and nothing more. It will make a pretty sight tomorrow morning before the sky gets too bright with reddish Mars being just below Saturn, by a bit less than 3 moon widths. Conjunctions of these two planets occur at intervals of two years give or take, since it involves the orbital motions of Mars and Saturn while viewing them from a third planet also orbiting the Sun.

Currently both planets are moving eastward against the stars. Saturn will slow and stop its motion on April 18th, while Mars will continue until June 28th. They will track westward for a while. This is because the Earth will be passing these planets this summer, which is called opposition (from the Sun).  Saturn will reach opposition on June 27th, Mars on July 27th.  Mars closest approach will occur four days later at a distance of 35.76 million miles  (57.59 million kilometers).  This is Mars’ closest approach to the Earth since August 27th, 2003.  Expect the return of the Mars hoax emails this summer.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Conjunction animation of Mars passing Saturn

Conjunction animation of Mars passing Saturn at daily intervals at 6 a.m. for March 30 to April 4, 2018. This will occur above the Teapot asterism of the constellation of Sagittarius. Created using Stellarium and GIMP.

I covered the Mars hoax 5 years ago here on an August 27th when Mars was nowhere close to us.

03/29/2018 – Ephemeris – The Easter date is set by the first full moon of spring and a developing conjunction

March 29, 2018 Comments off

Ephemeris for Thursday, March 29th. The Sun will rise at 7:29. It’ll be up for 12 hours and 37 minutes, setting at 8:06. The Moon, 2 days before full, will set at 7:21 tomorrow morning.

This Sunday, April 1st will be Easter for western churches. Because it falls on the first Sunday after the first full moon since March 21st. The Full Moon is Saturday the 31st. It happens that Passover begins at sundown the 31st. Orthodox churches will celebrate Easter on April 8th, a week later. It’s going to be a somewhat busy weekend in the sky also. Sunday Mercury will pass from the evening sky to the morning sky in an event called an inferior conjunction of the Sun. It is not visible, but folks in the southern hemisphere will easily spot Mercury late in April. In the morning sky Mars will pass below Saturn between the mornings of the 2nd and 3rd. They are close to the same brightness, but Mars is distinctly redder.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Conjunction animation of Mars passing Saturn

Conjunction animation of Mars passing Saturn at daily intervals at 6 a.m. for March 30 to April 4, 2018. This will occur above the Teapot asterism of the constellation of Sagittarius. Created using Stellarium ans GIMP.

02/09/2018 – Ephemeris – Morning planet high jinx

February 9, 2018 Comments off

Ephemeris for Friday, February 9th. The Sun will rise at 7:51. It’ll be up for 10 hours and 11 minutes, setting at 6:02. The Moon, 2 days past last quarter, will rise at 4:05 tomorrow morning.

This past Wednesday morning the Moon passed Jupiter, Earlier this morning the Moon passed north of Mars, and on Sunday morning Saturn will appear south of The Moon. There is a once in about 2 year event, that is red Mars passing Antares, the red giant star in Scorpius, one of the easiest constellations to spot because it actually resembles a scorpion. The name Antares means “Rival of Mars” because they have the same color: Ant meaning anti and Ares is the Greek god of war and counterpart of the Roman god Mars. Mars will pass Antares on average of

every 22 ½ months, its period around the Sun. Since we are viewing it from a moving Earth, it varies. Mars will pass Antares next on January 19th, 2020.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Morning planets and the Moon

Morning planets and the Moon at 7 a.m. on the mornings of February 9, 10 and 11, 2018.  See Mars changing position compared to Antares. Click on image to enlarge. Created using Stellarium and GIMP.